For a number of years removable roof units have been made which are used, for example, for the construction of winter-summer swimming pools. Generally, the roof, supported by pillars or poles during the cold season, is transferred in summer onto another series of poles installed permanently beside the previous ones. According to a variant embodiment, the roof is made up of arc-shaped panels made to pivot by a turning movement around a central mast, the unit traveling on a rail. Both of these systems exhibit a certain number of drawbacks both on the aesthetic and technical and technical plane; for example, the need of a double carrying structure in the first case, and, in the second case, the constant presence on the roof of at least a panel or section of panels under which the other panels fold. Further, in these known techniques, the dimensions are limited and removable roofs with a very large surface, for example, more than 1000 m.sup.2, cannot be realized.